On Fractional Fourier Transform Moments Based On Ambiguity FunctionCSCJournals
The fractional Fourier transform can be considered as a rotated standard Fourier transform in general and its benefit in signal processing is growing to be known more. Noise removing is one application that fractional Fourier transform can do well if the signal dilation is perfectly known. In this paper, we have computed the first and second order of moments of fractional Fourier transform according to the ambiguity function exactly. In addition we have derived some relations between time and spectral moments with those obtained in fractional domain. We will prove that the first moment in fractional Fourier transform can also be considered as a rotated the time and frequency gravity in general. For more satisfaction, we choose five different types signals and obtain analytically their fractional Fourier transform and the first and second-order moments in time and frequency and fractional domains as well.
The document discusses the Cilk programming language and its runtime system for parallel programming. Cilk extends C with keywords like spawn and sync to express parallelism. It provides performance guarantees and automatically manages scheduling across processors. The runtime system uses work-stealing to map Cilk threads to processors with near-optimal efficiency. Cilk allows expressing parallelism while hiding low-level details like load balancing.
The document discusses procedure activations and lifetimes. It provides an example of an activation tree for a quicksort program, showing the nested calls to procedures like partition and quicksort. It describes how activation records are used to store state and pass parameters during procedure calls, including the use of control links and access links to manage nested procedures and nonlocal data.
The document presents a new approach called FPERT (Fuzzy PERT) for project network analysis that accounts for uncertainty in activity times. It begins with an overview of FPERT and its advantages over conventional PERT. It then discusses key concepts needed for FPERT like fuzzy sets, membership functions, and α-cuts. The document outlines the steps of the proposed FPERT method and provides an example calculation. It concludes by introducing notation that will be used to calculate earliest start, earliest finish, latest start and latest finish times for activities.
Symbolic Execution as DPLL Modulo TheoriesQuoc-Sang Phan
The document discusses symbolic execution, which is a program analysis technique that executes programs with symbolic inputs instead of concrete inputs. It describes symbolic execution as an approach for solving satisfiability modulo theories (SMT) problems, by viewing symbolic execution as an SMT solver. It presents an implementation of symbolic execution based on a Boolean executor that performs a depth-first search, combined with an SMT solver to check satisfiability of path conditions.
XLNET, RoBERTa, and Reformer are state-of-the-art language models. XLNET improves on BERT by capturing dependency between target pairs. RoBERTa further improves pre-training by removing the next sentence prediction objective, training longer sequences with bigger batches. Reformer introduces efficient attention and feedforward mechanisms like reversible layers and locality-sensitive hashing to process long sequences with less memory.
On Fractional Fourier Transform Moments Based On Ambiguity FunctionCSCJournals
The fractional Fourier transform can be considered as a rotated standard Fourier transform in general and its benefit in signal processing is growing to be known more. Noise removing is one application that fractional Fourier transform can do well if the signal dilation is perfectly known. In this paper, we have computed the first and second order of moments of fractional Fourier transform according to the ambiguity function exactly. In addition we have derived some relations between time and spectral moments with those obtained in fractional domain. We will prove that the first moment in fractional Fourier transform can also be considered as a rotated the time and frequency gravity in general. For more satisfaction, we choose five different types signals and obtain analytically their fractional Fourier transform and the first and second-order moments in time and frequency and fractional domains as well.
The document discusses the Cilk programming language and its runtime system for parallel programming. Cilk extends C with keywords like spawn and sync to express parallelism. It provides performance guarantees and automatically manages scheduling across processors. The runtime system uses work-stealing to map Cilk threads to processors with near-optimal efficiency. Cilk allows expressing parallelism while hiding low-level details like load balancing.
The document discusses procedure activations and lifetimes. It provides an example of an activation tree for a quicksort program, showing the nested calls to procedures like partition and quicksort. It describes how activation records are used to store state and pass parameters during procedure calls, including the use of control links and access links to manage nested procedures and nonlocal data.
The document presents a new approach called FPERT (Fuzzy PERT) for project network analysis that accounts for uncertainty in activity times. It begins with an overview of FPERT and its advantages over conventional PERT. It then discusses key concepts needed for FPERT like fuzzy sets, membership functions, and α-cuts. The document outlines the steps of the proposed FPERT method and provides an example calculation. It concludes by introducing notation that will be used to calculate earliest start, earliest finish, latest start and latest finish times for activities.
Symbolic Execution as DPLL Modulo TheoriesQuoc-Sang Phan
The document discusses symbolic execution, which is a program analysis technique that executes programs with symbolic inputs instead of concrete inputs. It describes symbolic execution as an approach for solving satisfiability modulo theories (SMT) problems, by viewing symbolic execution as an SMT solver. It presents an implementation of symbolic execution based on a Boolean executor that performs a depth-first search, combined with an SMT solver to check satisfiability of path conditions.
XLNET, RoBERTa, and Reformer are state-of-the-art language models. XLNET improves on BERT by capturing dependency between target pairs. RoBERTa further improves pre-training by removing the next sentence prediction objective, training longer sequences with bigger batches. Reformer introduces efficient attention and feedforward mechanisms like reversible layers and locality-sensitive hashing to process long sequences with less memory.
This document provides an overview of building a simple one-pass compiler to generate bytecode for the Java Virtual Machine (JVM). It discusses defining a programming language syntax, developing a parser, implementing syntax-directed translation to generate intermediate code targeting the JVM, and generating Java bytecode. The structure of the compiler includes a lexical analyzer, syntax-directed translator, and code generator to produce JVM bytecode from a grammar and language definition.
This document discusses the class P of computational problems that can be solved in polynomial time on a deterministic Turing machine. It begins with reviewing homework on big O notation and time complexity. It then provides examples comparing the run times of problems that are polynomial, exponential, and factorial in time. It defines the class P as problems decidable in polynomial time by a Turing machine. It discusses some example problems in P, like the PATH problem.
Inversion Theorem for Generalized Fractional Hilbert Transforminventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Optimal control of multi delay systems via orthogonal functionsiaemedu
This document discusses a unified approach for computing the optimal control of linear time-invariant/time-varying systems with time delays using orthogonal functions like block-pulse functions (BPFs) and shifted Legendre polynomials (SLPs). It reviews previous work on optimal control of time-delay systems and presents a new approach that directly expresses the unknown state x(t) in terms of orthogonal functions to obtain the state feedback control law u(t). The approach also handles the final cost term in the performance index differently than previous methods. Numerical examples are provided to demonstrate the applicability of the unified approach.
The document discusses run-time environments and activation records. It explains that activation records are used to manage information for each procedure call and are allocated on the stack. Activation records contain fields for return values, parameters, local variables, and more. When a procedure is called, its activation record is pushed onto the stack and popped off when it returns. Activation records allow recursive calls by creating a new record each time a procedure is activated.
The price density function, a tool for measuring investment risk,volatility a...Tinashe Mangoro
In this paper I derive a density function for describing the distribution of an investment;s price.From that function I then go on to show how we can use it to calculate volatility, interest rate averages and also hedging risk againist interest rate movements.
1) Complexity classes categorize problems based on the time and space complexity of their solutions. P represents problems solvable in polynomial time, while NP includes problems verifiable in polynomial time.
2) NP-hard problems are at least as hard as any problem in NP, and NP-complete problems are both in NP and NP-hard - they are the most difficult problems in NP.
3) Reducibility is used to prove problems are NP-complete - if problem A can be reduced to problem B in polynomial time, and B is NP-complete, then A is also NP-complete. 3-SAT is reduced to the clique problem by creating graph vertices for each literal.
This document compares several methods for fundamental frequency estimation and voicing decision from speech signals. It presents four methods: a SIFT-based method, a Frobenius norm method, and two bilinear time-frequency representation methods using different kernels. The document describes the processing steps common to the methods and evaluates their performance on a database of speech signals using metrics like gross error rates for fundamental frequency estimation and glottal closure instant detection accuracy. The bilinear time-frequency method using a Born-Jordan kernel achieved the best glottal closure instant detection, while the SIFT method was more robust to inter-speaker variability.
The document discusses for loops in Python. It explains that for loops are used to iterate over sequences like lists, tuples, and strings. There are two types of for loops: 1) Getting each element of the sequence, and 2) Using the range() function to generate a sequence of numbers to use as indexes. The document provides examples of iterating over lists and strings using for loops, and using break and continue statements to control loop behavior. It also explains how to use the range() function to generate a sequence of numbers for iteration.
Introduction on Prolog - Programming in LogicVishal Tandel
Prolog is a logic programming language that is used for construction project management. It allows organizations to automate tasks and processes, streamline project delivery, control costs through real-time budget tracking, increase productivity through remote collaboration, reduce legal risks with audited access to documents, monitor project performance with dashboards, and integrate construction data with other systems. Over 6,000 organizations have used Prolog as the industry standard to manage construction projects and provide transparency to stakeholders.
Introduction to return oriented programming. Explanation of how to use instruction sequences already existing in an executable's memory space to manipulate control flow without injecting external payload.
The document discusses various programming concepts in C# including namespaces, data conversion, relational operators, Boolean expressions, and conditional control structures like if, else if, and switch statements. Namespaces are used to organize code elements and create unique types. The Convert class contains methods for converting between data types like strings and numbers. Conditional statements like if/else and switch/case allow for executing different blocks of code depending on conditional expressions being true or false.
The component computes backward probability density functions (pdfs) of residence time, travel time, and evapotranspiration time given actual time based on a water budget equation. It solves the equation to obtain the pdfs in matrices with injection time and current time as dimensions. The mean travel and evapotranspiration times can be computed by integrating the pdfs over injection time. Examples of input files and parameter settings are provided.
Añotador is a temporal tagger for Spanish created by researchers at the Universidad Politécnica de Madrid. It detects and normalizes temporal expressions like dates, times, durations, and sets in Spanish text. The researchers built a corpus called Hourglass to evaluate temporal taggers for Spanish, as existing resources were limited. Añotador achieved the best performance on the Hourglass corpus compared to other taggers. While Añotador performed well, the researchers note there is still work to be done, such as improving handling of challenging temporal expressions.
This document describes a new mechanism for predicting stale queries in a search engine's result cache. It uses timestamps to track changes to documents and terms in the index. When a cached query is requested, the timestamps are used to check if the query results may be stale due to document deletions, updates, or new documents matching the query terms. Experiments show this approach reduces redundant query executions compared to a simple time-to-live approach, while achieving a prediction accuracy comparable to prior work with lower overhead.
GEOframe-NewAge: documentation for probabilitiesbackward componentMarialaura Bancheri
This document provides information about the ProbabilitiesBackward component in OMS 3, which computes backward probability density functions (pdfs) of residence time, travel time, and evapotranspiration time given actual time and input data. The component solves an ordinary differential equation to obtain the pdfs as tridimensional matrices. It also calculates the mean travel and evapotranspiration times by integrating the output matrices over injection time. Details are provided on the component's inputs like rainfall, storage, evapotranspiration, and outputs including the various pdfs and mean times.
A bitemporal nested query language, BTN-SQL, is
proposed in this paper. BTN-SQL attempts to fill some gaps
present in currently available SQL standards. BTN-SQL
extends the well-known SQL syntax into two directions, the
user-friendliness support of nested relations and the effective
support of bitemporal data. The schema of a bitemporal nested
database is difficult to be understood since it is complicated
by nature; therefore, an extended approach of the Entity-
Relationship model, the BTN-ER model, is also proposed for
modelling complex bitemporal nested data.
The GO4IT project aims to:
1) Raise awareness and prepare users for the transition to IPv6.
2) Expand the IPv6 user community.
The project provides a free IPv6 validation environment including test tools, test suites, and related services. BUPT's tasks include designing abstract test suites in TTCN-3 for conformance and interoperability testing of technologies like mobile IPv6. BUPT will also work on software components for test development and execution like the TTCN-3 compiler and test adapters.
1. TTCN was originally developed to test telecommunication systems but has expanded to other industries like automotive. It aims to make testing more efficient, automated, and reproducible.
2. TTCN-3 introduced new capabilities like procedure-based communication and dynamic test configuration control to broaden the scope of testable applications. It also standardized target adaptation interfaces.
3. TTCN is used for black box testing where tests stimulate interfaces and check responses without knowledge of internal implementation. It uses abstract test cases, parallel test components, and standardized interfaces to connect executable test suites to the system under test.
Scott Bailey
Few things we model in our databases are as complicated as time. The major database vendors have struggled for years with implementing the base data types to represent time. And the capabilities and functionality vary wildly among databases. Fortunately PostgreSQL has one of the best implementations out there. We will look at PostgreSQL's core functionality, discuss temporal extensions, modeling temporal data, time travel and bitemporal data.
The document presents a method for clustering and exploring search results using timelines. It describes annotating documents with temporal metadata, constructing time outlines from the metadata to organize search results chronologically, and clustering documents based on time granularity. An evaluation using Amazon Mechanical Turk found the method improved search result relevance by adding temporal context and snippets.
This document provides an overview of building a simple one-pass compiler to generate bytecode for the Java Virtual Machine (JVM). It discusses defining a programming language syntax, developing a parser, implementing syntax-directed translation to generate intermediate code targeting the JVM, and generating Java bytecode. The structure of the compiler includes a lexical analyzer, syntax-directed translator, and code generator to produce JVM bytecode from a grammar and language definition.
This document discusses the class P of computational problems that can be solved in polynomial time on a deterministic Turing machine. It begins with reviewing homework on big O notation and time complexity. It then provides examples comparing the run times of problems that are polynomial, exponential, and factorial in time. It defines the class P as problems decidable in polynomial time by a Turing machine. It discusses some example problems in P, like the PATH problem.
Inversion Theorem for Generalized Fractional Hilbert Transforminventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Optimal control of multi delay systems via orthogonal functionsiaemedu
This document discusses a unified approach for computing the optimal control of linear time-invariant/time-varying systems with time delays using orthogonal functions like block-pulse functions (BPFs) and shifted Legendre polynomials (SLPs). It reviews previous work on optimal control of time-delay systems and presents a new approach that directly expresses the unknown state x(t) in terms of orthogonal functions to obtain the state feedback control law u(t). The approach also handles the final cost term in the performance index differently than previous methods. Numerical examples are provided to demonstrate the applicability of the unified approach.
The document discusses run-time environments and activation records. It explains that activation records are used to manage information for each procedure call and are allocated on the stack. Activation records contain fields for return values, parameters, local variables, and more. When a procedure is called, its activation record is pushed onto the stack and popped off when it returns. Activation records allow recursive calls by creating a new record each time a procedure is activated.
The price density function, a tool for measuring investment risk,volatility a...Tinashe Mangoro
In this paper I derive a density function for describing the distribution of an investment;s price.From that function I then go on to show how we can use it to calculate volatility, interest rate averages and also hedging risk againist interest rate movements.
1) Complexity classes categorize problems based on the time and space complexity of their solutions. P represents problems solvable in polynomial time, while NP includes problems verifiable in polynomial time.
2) NP-hard problems are at least as hard as any problem in NP, and NP-complete problems are both in NP and NP-hard - they are the most difficult problems in NP.
3) Reducibility is used to prove problems are NP-complete - if problem A can be reduced to problem B in polynomial time, and B is NP-complete, then A is also NP-complete. 3-SAT is reduced to the clique problem by creating graph vertices for each literal.
This document compares several methods for fundamental frequency estimation and voicing decision from speech signals. It presents four methods: a SIFT-based method, a Frobenius norm method, and two bilinear time-frequency representation methods using different kernels. The document describes the processing steps common to the methods and evaluates their performance on a database of speech signals using metrics like gross error rates for fundamental frequency estimation and glottal closure instant detection accuracy. The bilinear time-frequency method using a Born-Jordan kernel achieved the best glottal closure instant detection, while the SIFT method was more robust to inter-speaker variability.
The document discusses for loops in Python. It explains that for loops are used to iterate over sequences like lists, tuples, and strings. There are two types of for loops: 1) Getting each element of the sequence, and 2) Using the range() function to generate a sequence of numbers to use as indexes. The document provides examples of iterating over lists and strings using for loops, and using break and continue statements to control loop behavior. It also explains how to use the range() function to generate a sequence of numbers for iteration.
Introduction on Prolog - Programming in LogicVishal Tandel
Prolog is a logic programming language that is used for construction project management. It allows organizations to automate tasks and processes, streamline project delivery, control costs through real-time budget tracking, increase productivity through remote collaboration, reduce legal risks with audited access to documents, monitor project performance with dashboards, and integrate construction data with other systems. Over 6,000 organizations have used Prolog as the industry standard to manage construction projects and provide transparency to stakeholders.
Introduction to return oriented programming. Explanation of how to use instruction sequences already existing in an executable's memory space to manipulate control flow without injecting external payload.
The document discusses various programming concepts in C# including namespaces, data conversion, relational operators, Boolean expressions, and conditional control structures like if, else if, and switch statements. Namespaces are used to organize code elements and create unique types. The Convert class contains methods for converting between data types like strings and numbers. Conditional statements like if/else and switch/case allow for executing different blocks of code depending on conditional expressions being true or false.
The component computes backward probability density functions (pdfs) of residence time, travel time, and evapotranspiration time given actual time based on a water budget equation. It solves the equation to obtain the pdfs in matrices with injection time and current time as dimensions. The mean travel and evapotranspiration times can be computed by integrating the pdfs over injection time. Examples of input files and parameter settings are provided.
Añotador is a temporal tagger for Spanish created by researchers at the Universidad Politécnica de Madrid. It detects and normalizes temporal expressions like dates, times, durations, and sets in Spanish text. The researchers built a corpus called Hourglass to evaluate temporal taggers for Spanish, as existing resources were limited. Añotador achieved the best performance on the Hourglass corpus compared to other taggers. While Añotador performed well, the researchers note there is still work to be done, such as improving handling of challenging temporal expressions.
This document describes a new mechanism for predicting stale queries in a search engine's result cache. It uses timestamps to track changes to documents and terms in the index. When a cached query is requested, the timestamps are used to check if the query results may be stale due to document deletions, updates, or new documents matching the query terms. Experiments show this approach reduces redundant query executions compared to a simple time-to-live approach, while achieving a prediction accuracy comparable to prior work with lower overhead.
GEOframe-NewAge: documentation for probabilitiesbackward componentMarialaura Bancheri
This document provides information about the ProbabilitiesBackward component in OMS 3, which computes backward probability density functions (pdfs) of residence time, travel time, and evapotranspiration time given actual time and input data. The component solves an ordinary differential equation to obtain the pdfs as tridimensional matrices. It also calculates the mean travel and evapotranspiration times by integrating the output matrices over injection time. Details are provided on the component's inputs like rainfall, storage, evapotranspiration, and outputs including the various pdfs and mean times.
A bitemporal nested query language, BTN-SQL, is
proposed in this paper. BTN-SQL attempts to fill some gaps
present in currently available SQL standards. BTN-SQL
extends the well-known SQL syntax into two directions, the
user-friendliness support of nested relations and the effective
support of bitemporal data. The schema of a bitemporal nested
database is difficult to be understood since it is complicated
by nature; therefore, an extended approach of the Entity-
Relationship model, the BTN-ER model, is also proposed for
modelling complex bitemporal nested data.
The GO4IT project aims to:
1) Raise awareness and prepare users for the transition to IPv6.
2) Expand the IPv6 user community.
The project provides a free IPv6 validation environment including test tools, test suites, and related services. BUPT's tasks include designing abstract test suites in TTCN-3 for conformance and interoperability testing of technologies like mobile IPv6. BUPT will also work on software components for test development and execution like the TTCN-3 compiler and test adapters.
1. TTCN was originally developed to test telecommunication systems but has expanded to other industries like automotive. It aims to make testing more efficient, automated, and reproducible.
2. TTCN-3 introduced new capabilities like procedure-based communication and dynamic test configuration control to broaden the scope of testable applications. It also standardized target adaptation interfaces.
3. TTCN is used for black box testing where tests stimulate interfaces and check responses without knowledge of internal implementation. It uses abstract test cases, parallel test components, and standardized interfaces to connect executable test suites to the system under test.
Scott Bailey
Few things we model in our databases are as complicated as time. The major database vendors have struggled for years with implementing the base data types to represent time. And the capabilities and functionality vary wildly among databases. Fortunately PostgreSQL has one of the best implementations out there. We will look at PostgreSQL's core functionality, discuss temporal extensions, modeling temporal data, time travel and bitemporal data.
The document presents a method for clustering and exploring search results using timelines. It describes annotating documents with temporal metadata, constructing time outlines from the metadata to organize search results chronologically, and clustering documents based on time granularity. An evaluation using Amazon Mechanical Turk found the method improved search result relevance by adding temporal context and snippets.
Chronological Decomposition Heuristic: A Temporal Divide-and-Conquer Strateg...Alkis Vazacopoulos
This document summarizes the chronological decomposition heuristic (CDH), a temporal divide-and-conquer strategy for solving production scheduling problems. The CDH decomposes the scheduling time horizon into smaller time chunks that are solved sequentially using MILP. It uses a depth-first search with backtracking to find feasible solutions. The document provides an example application of the CDH to a small crude oil blending scheduling problem, showing it finds optimal or near-optimal solutions faster than solving the full problem at once.
This document provides information about the CS213 Programming Languages Concepts course taught by Prof. Taymoor Mohamed Nazmy in the computer science department at Ain Shams University in Cairo, Egypt. It describes the syntax and semantics of programming languages, discusses different programming language paradigms like imperative, functional, and object-oriented, and explains concepts like lexical analysis, parsing, semantic analysis, symbol tables, intermediate code generation, optimization, and code generation which are parts of the compiler design process.
This document provides an overview of how compilers work by summarizing their main components and processes. It explains that a compiler translates a program written in a high-level language into an equivalent program in a lower-level language. The compilation process involves two main stages - analysis and synthesis. Analysis breaks down the source code and generates an intermediate representation, while synthesis constructs the target program from that representation. Key phases in each stage, such as lexical analysis, parsing, code generation and optimization, are also outlined.
Transaction Timestamping in Temporal DatabasesGera Shegalov
This document summarizes techniques for timestamping transactions in temporal databases to ensure consistency across distributed systems. It discusses using timestamps to serialize transactions and maintain valid transaction histories when transactions occur concurrently. Key techniques include assigning timestamps at commit time to establish order, using a read timestamp table to synchronize reads and writes, and coordinating timestamps across databases in distributed transactions using two-phase commit.
The document provides an overview of time-triggered architecture (TTA) and communication protocols. TTA treats physical time as fundamental and provides a fault-tolerant global time base. It decomposes applications into clusters, nodes, and their interfaces. Communication is specified via global time and time-triggered protocols like TTP/C and FlexRay are used. TTA architecture consists of nodes with host and communication subsystems connected via a time-triggered bus.
A fast-paced introduction to TensorFlow 2 about some important new features (such as generators and the @tf.function decorator) and TF 1.x functionality that's been removed from TF 2 (yes, tf.Session() has retired).
Some concise code samples are presented to illustrate how to use new features of TensorFlow 2.
The document analyzes how the lexicon (identifiers) and structure of programs evolve over multiple versions of three software systems: Eclipse, Mozilla, and CERN/Alice. It finds that the lexicon is generally more stable than structure and that renaming of identifiers is rare. Some reasons why the lexicon is reluctant to change include the cognitive burden of changes and lack of dedicated renaming tools. The study concludes that more research is needed on tools to help preserve and improve a program's lexicon over time.
This document discusses a proposed look-ahead finite automata (LaFA) system for improving regular expression (RE) detection speed in network intrusion detection and prevention systems (NIDPS). The LaFA approach aims to address scalability issues with existing RE detection methods by optimizing the detection sequence, sharing states among automata for different REs, and using specialized buffered lookup modules for detection. These modules include a timestamps lookup module, character lookup module, and repetition detection module that can perform "look ahead" operations to more efficiently detect variable string patterns in REs. The proposed LaFA architecture and detection modules are described and compared to existing deterministic and nondeterministic finite automata approaches.
Data Structure and Algorithm chapter two, This material is for Data Structure...bekidea
The document discusses algorithm analysis and different searching and sorting algorithms. It introduces sequential search and binary search as simple searching algorithms. Sequential search, also called linear search, examines each element of a list sequentially until a match is found. It has average time complexity of O(n) as it may need to examine all n elements in the worst case.
This document summarizes a final project report for a parallel text mining framework that analyzes tweets in real-time. The project crawls tweets from major news outlets using Twitter's API and analyzes each tweet using hidden Markov models for part-of-speech tagging. The analysis is performed in parallel across 30 machines with 16 cores each using MPI. Bottlenecks include Twitter's API rate limits and scraping news articles, which are addressed through multi-threading and batch processing tweets.
Similar to TETI: a TimeML Compliant TimEx Tagger for Italian (20)
1. TETI: a TimeML Compliant TimEx
Tagger for Italian
Tommaso Caselli, Felice dell'Orletta and Irina Prodanof
Istituto di Linguistica Computazionale “A. Zampolli” - ILC-CNR Pisa
{firstName.secondName@ilc.cnr.it}
IMCSIT 2009 – CL-A09, Mragawo, October, 13
2. Outline:
Motivations
Extracting Temporal expression and the TIMEX3
tag
TETI:
− System architecture
− Demo
Evaluation
Conclusions & Future Work
3. Motivations
Recovering temporal relations in text/discourse is essential to
improve the performance of many NLP systems (O.D-Q.A., Text
Mining, Summarization, Reasoning)
Most temporal information in text/discourse is only IMPLICITLY
stated
Need to develop procedures to maximize the role of the various
sources of information
Temporal expressions represent a source of explicit temporal
knowledge which can:
− Locate an eventuality in time, and thus used for
inferencing for temporal relations between eventualities
− Measure the duration of an eventuality
4. Extracting Temporal Expressions
The extraction of timexes can be divide into 4
subtasks:
− Recognizing and bracketing the timex
− Feature extraction (type of time unit, referential
status, presence of modifiers)
− Computing the interval of reference on the time
line
− Resolving the timex, i.e. normalize the value to a
standard output format
5. Extracting Temporal Expressions
The extraction of timexes can be divide into 4
subtasks:
− Recognizing and bracketing the timex
− Feature extraction (type of time unit,
referential status, presence of modifiers)
− Computing the interval of reference on the time
line
− Resolving the timex, i.e. normalize the value to a
standard output format
6. Temporal Expressions in TimeML:
The TIMEX3 tag
TIMEX3 tag extends and improves previous tags for this task,
namely TIMEX, TIDES TIMEX2
TIMEX3 tag is used to mark any time word i.e. both absolute
and relative timexes such as day time (midnight..), dates of
different granularity (yesterday, last spring..), calendar dates
(01/12/1980..), durations (three hours, two years..), set of time
(yearly, every day..)
The annotation process is based on:
− the constituent structure (NP, AdjP, AdvP, Time/Date
Pattern)
− the granularity of the time units
− the relations between the timexes
7. TETI: Temporal Expression Tagger
for Italian
Rule-based system
Main components:
Chunked text
TIMEX
DETECTOR &
TIMEX TAGGER
Two external
resources: TimEx
Trigger Dictionary
and a Modifier
Dictionary
10. TETI: Temporal Expression Tagger
for Italian (2)
Chunker output
approximate
TIMEX3 tag
extent
Extent of timexes
corresponds to
regolar patterns of
combination of
chunks
11. TETI: Temporal Expression Tagger
for Italian (3)
Analysis of the
chuncked text
Chunked text
Lookout in the
TimeEx Trigger
dictionary
Extraction of the
necessary features
for the bracketing
13. TETI: Temporal Expression Tagger
for Italian (4)
Core element of
the tagger
Chunked text
A general
condition + set of
local conditions
If the conditions
are true, the tagger
activates the
related rules and
brackets the timex
with TIMEX3
17. TETI: Temporal Expression Tagger
for Italian (5)
More complex
timexes require a
Chunked text further lookup in
the TimEx Trigger
Dictionary to
extract further
features (sematic
relations) for the
correct bracketing
19. Evaluation
42 newpaper articles manually annotated
367 timexes
TAG TOT CORR. MISSING INCORR. P R F
TIMEX3 367 321 35 66 82.95 90.17 86.41
TIMEX3: 90 55 12 23 82.09 70.51 75.86
modificatori
20. Conclusion & Future Work
• Reduction of the number of false positives
• Implemetation of the normalization phase → rule
based
• Re-wrting of the rules to be compliant with the
KAF format (KYOTO Project)
• Release of the tool via web service
21. Acknowlegments
Thanks to Roberto Bartolini for his help in the
development of the demo